Historical analysis of battery cells for determining state of health

A computer program product, comprising:

• a non-transitory computer readable medium comprising:
• code to count the number of times a battery cell of an array of battery cells is out of balance with other battery cells;
• code to determine a Coulomb threshold level based, in part, on the counted number of times;
• code to count a number of Coulombs the battery cell is out of balance with the other battery cells;
• and
• code to set a state-of-health flag when the counted number of Coulombs exceeds the Coulomb threshold.

An apparatus, comprising:

• a memory;
• and
• at least one processor, in which the at least one processor is configured:
• to count the number of times a battery cell of an array of battery cells is out of balance with other battery cells;
• to determine a Coulomb threshold level based, in part, on the counted number of times;
• to count a number of Coulombs the battery cell is out of balance with the other battery cells;
• and
• to set a state-of-health flag when the counted number of Coulombs exceeds the Coulomb threshold.